Operating mechanism for electrical circuit breaker of the gas blast type



June 14, 1966 s. GIAMMONA ETAL 3,256,414

OPERATING MECHANISM FOR ELECTRICAL CIRCUIT BREAKER OF THE GAS BLAST TYPE Filed March 29. 1963 INVENTORS Salvatore Glam menu,

/ a.rL Holzinger Friedrich HonLr nger United States Patent 3,256,414 OPERATING MECHANISM FOR ELECTRICAL CIR- CUIT BREAKER OF THE GAS BLAST TYPE Salvatore Giamrnona and Karl' Holzinger, Nussbaumen, and Friedrich Honlinger, Baden, Switzerland, assignors to Aktiengesellschaft Brown, Boveri & Cie, Baden, Switzerland, a joint-stock company Filed Mar. 29, 1963, Ser. No. 268,887 Claims priority, application Switzerland, Mar. 30, 1962, 3,929/62; Apr. 26, 1962, 5,027/62 4 Claims. (Cl. 200--148) This invention relates to an improvement in an operating mechanism for a gas blast circuit-breaker with one or more interruption points where the valves for the pneumatic operation of the arc extinction chambers are located on live parts of the breaker and are controlled from the earthed lower part of the breaker by way of insulated rods.

Airblast circuit-breakers are known where the valves for the pneumatic operation of the switching elements are located in the immediate vicinity of the switching cont-acts and are thus on the live part of the breaker. This results in short switching times and a low consumption of pressure gas, because the supply pipes and chambers between the live parts and'the e-arthed lower part of the breaker which have to be filled with compressed air can be dispensed with. With this conventional type of airblast breaker the valves are actuated either pneumatically or hydraulically ,by way of control pipes or mechanically with insulated rods. The constant increase in the system short-circuit currents results in an endeavor to construct the ciruit-breaker so as to reduce as much as possible the switching times, particularly the breaking time of the circuit-breaker. In this connection the rapid transmission of the switching orders from the lower part of the breaker to the switch chambers is particularly important. Pneumatic and hydraulic transmissions are, however, restricted in this respect. Moreover, such systems require a relatively large amount of space and are subject to disturbances, because of the additional pipes and control elements. The known types of mechanical transmission systems also possess certain disadvantages due to the fact that the. switching valves located on the live parts of the breaker have powerful springs which are connected by insulating rods to pneumatic pistons in the lower part of the breaker, these pistons when in the position of rest being subjected on both sides to a gas pressure whilst during a switching operation thegas is exhausted from one side whereby the valve is opened against the direction of flow by means of the pistonand insulating rod. The insulating rod has thus to transmit the entire opening force and must therefore be of correspondingly robust construction. Its mass which has to be accelerated is' relatively large, so that the switching time is detrimentally affected.

In order to avoid the aforementioned disadvantages it is now proposed according to the invention that always at least one switching valve, actuated by compressed gas and opening in the direction of flow, is connected by way of a tension rodding elastically prestressed in the closed position'to devices on the lower part of the breaker in such a manner that these devices eifect the opening and closing of the switching valves. With this arrangement, during the breaking operation, the pressure gas acts directly on the valve whilst the insulating rodding can follow freely without having to transmit the opening force. It can therefore be constructed in the form' of a low-mass flexible element whereby the breaking time is considerably reduced.

FIG. 1 shows a constructional example of the new arrangement, the device at the lower part of the breaker being a differential piston.

FIG. 2 shows the device at the lower part of the breaker in the form of a spring loaded pressure gas piston.

FIG. 3 shows a further modified form where the device at the lower part of the breaker is constructed as an interlock.

FIG. 1 shows a gas blast circuit-breaker the lower part of which is constructed in the form of a pressure gas container. By way of the hollow supporting insulator 2 which forms the earth insulation, the pressure gas container 1 is in pneumatic communication with the intermediate container 3.1 which is under voltage. Reference number 4.1 indicates the actuating device for the switching point or points which are not shown and are associated with the container 3.1. The actuating device 4.1 comprises a casing 5.1 in which a piston 6.1 is located which by means of a piston rod 7.1 is connected to a movable switch contact, not shown in the drawing. Casing 5.1 has a chamber 8.1 which communicates with the atmosphere by way of openings 9.1 and 10.1. The inlet conduit 11.1 connects container 3.1 with chamber 8.1 and in the position shown in the figure is closed by the disc 12.1 of the switching valve. Valve disc 12.1 is connected to the insulating rod 17.1 and 17.2 at the point 16.1 byway of the valve rod 13.1 and lever 15.1 which is pivoted at 14.1. Valve rod 13.1 is also provided with a spring plate 18.1 against which a recall spring 19.1 abuts. In the selected constructional example a further intermediate container 3.2 is provided above container 3.1. These containers 3.1 and 3.2 are in pneumatic communication with each other by means of the insulator 20. Container 3.2 contains like container 3.1 a driving device 4.2, casing 5.2 with piston 6.2, piston rod 7.2, chamber 8.2, openings 9.2 and 10.2, as well as a switching valve with a valve disc 12.2 which closes the inlet conduit 11.2 and is linked by way of valve rod 13.2 and lever 15.2, pivoted at 14.2, to the insulating rod 17.2 at the point 16.2. Valve rod 13.2 carries the spring plate 18.2 against which spring 19.2 abuts. The switching points which are not shown and are associated withcontainers 3.1 and 3.2 can be connected electrically in series in a known manner, whereby multiple interruption is obtained. The insulating rod 17.1, which for instance consists of a flexible synthetic material with glass fibre reinforcement, has at its lower end a holder 16.3 by means of which it is connected to the differential piston 22' located in casingv 21. The space above the differential piston 22 is connected by a pipe 23 to the pressure gas container 1, whilst the space underneath the piston 22 can be shut off by the sleeve valve 27 and is in communication with container 1 by way of pipe 24; Sleeve valve 27 carries a pin 28 to which a double-armed lever 29 pivoted at 30 is connected. The sleeve valve 27 is actuated by rodding indicated at 31 and connected in a known manner to a control device which is not shown. The differential piston 22 has a narrow hole 25 through which air can enter or leave the chamber 26. The insulating rods 17.1 and 17.2 are arranged inside the hollow insulators 32.1 and 32.2.

The arrangement operates as follows:

It is assumed that the circuit-breaker is in the closed position. In order to open the breaker, rodding 31 is moved upwards as indicated by the arrow. This causes sleeve valve 27 to be moved into its lower end position by means of lever 29. Whilst previously the space below the larger surface of the difierent'ial piston 22 was in communication by way of sleeve 27 with the atmosphere, pressure gas now passes from container 1 through pipe 24, underneath piston 22 and the interior of sleeve 27 is shut off from the atmosphere. The closing force acting by the same reference numerals.

on valve discs 12.1 and 12.2 is thus suspended. This closing force, in the closing position of the breaker, starting from piston 22.subjected on its upper side to pressure gas from pipe 23, is transmitted by way of elastically prestressed insulating rods 17.1 and 17.2, levers 15.1 and 15.2, valve rods 13.1 and 13.2 to valve discs 12.1 and 12.2. The pressure gas in containers 3.1 and 3.2 thus acts through conduits 11.1 and 11.2 on valve discs 12.1 and 12.2 in thedownward direction with increasing speed, whereby chambers 8.1 and 8.2 are filled and pistons 6.1 and 6.2 are moved to the leftso that the switch contacts are opened. In their lowest position, valve discs 12.1 and 12.2 close the openings 9.1 and 9.2 by means of which chambers 8.1 and 8.2 were previously in pressure-free communication with the atmosphere by wayof openings 10.1 and 10.2. During the opening operation described above, insulating rods 17.1 and 17.2 move upwards whereby their flexible prestressing can be equalized to the extent that the differential piston 22 to which they are connected follows. The acceleration of piston 22 is assisted by the excess surface, because the narrowborehole 25 only enables space .26 to be filled appreciably towards the end of the movement, a compression damping effect being achieved during the last part of the stroke. The length of the'insulating rods 17.1 and 17.2 and a stop provided for the piston 22 in casing 21, are expediently so selected that valve discs 12.1 and 12.2 which in their lower limiting position close the openings 9.1 and 9.2 maintain a certain flexible prestressing of the insulating rods by way of the valve rods 13.1 and 13.2 and levers 15.1, 15.2.

For closing the circuit breaker, sleeve valve 27 is "moved upwards -by means of rodding 31 andlever 29 back into the position shown in the drawing. The space below. the larger surface of piston 22 is thus connected to the at mosphere and relieved of its gas pressure. Due to the pressure prevailing on the upper smaller surface of piston 22 and partly due to the pressure in space 26, the piston moves downwards and by means of insulating. rods 17.1 and 17.2 causes levers 15.1 and 15.2, valve rods 13.1 and 13.2, and valve discs 12.1 and 12.2 to return to the position shown. Chambers 81 and 8.2 are exhausted, so that pistons 6.1 and 6.2 can move to the right and the switch contacts are closed by suitable means, such as for instance springs. Since, as already described, the insulating rods 17.1 and 17.2 also in the open position of the breaker are subjected to a certain flexible prestress, for the closing operation it is only necessary to achieve a slight flexible deformation in order to reduce the closing time. The return springs 19.1 and '19.2. can be comparatively weak, so that they have practically no retarding effect on the switching operations.. They merely serve to ensure that when the breaker is filled with pressure gas, e.g. initial assembly or afteran'overhauL-the valve discs 12.1 and 12.2 are certain to be in the upper end position so that pressure gas cannot escape, for instance through the openings 9.1, 10.1 and 9.2, 10.2.

For outdoor installations it is advisable to arrange the valve27, as well as elements 28 to 31 correspond to those of FIG. 1.

The method of operation is as follows:

In the position shown, corresponding to the closed position of the breaker, the insulating rod 17.1 is flexibly prestressed by the pressure spring 33. In order to open the breaker, sleeve valve 27 moves into the lower end position in the manner already described in connection with FIG. 1, whereupon piston 32 moves upwards due to the effect of the incoming pressure gas. To close the breaker, sleeve valve 27 is returned to its former position whereby the space below the piston 32 is exhausted, so that the piston and insulating rod, due to the effect of spring 33, are returned to the position shown in the figure. This arrangement enables a simple form of piston to be used and the pipe 23 shown in FIG. 1 can be dispensed with. By limiting the stroke of the piston 32 it is possible, as in the case of FIG. 1, to maintain the insulating rod elastically prestressed when in the opening position.

FIG. 3 shows a further modified form of operating mechanism on the lower part of the breaker. In this case, the insulating rod 17.1 is pivotally connected by way of the holder 16.3 to a retaining latch 34. This latch 34 Y is provided with a recess which engages a fixed pin 35 insulating rods 17.1 and 17.2 inside the hollow insulators 32.1 and 32.2 which'are expediently filled with compressed gas. Levers 15.1 and 15.2, for instance on a common shaft, which is supported in a pressure-tight manner inside a fitting of the hollow insulators, can then be constructed with laterally displaced arms in such a manner that one arm is outside the fitting in the open-air and the other :arm inside the pressure-gas filled fitting.

Another form of device in accordance with the invention at the lower part of the circuit-breaker for actuating the insulating rods is illustrated in FIG. 2.

Parts corresponding to those of FIG. 1 are designated The insulating rod 17.1 is connected by means of the holder 16.3 to a piston 32 which is located in a casing 21 and is subjected to the pressure of a spring 33. The space below the piston is .connected to container 1 by means of a pipe 24. Sleeve and in the interlocking position is held there by an arm of an angle-lever 36. The other arm of the angle-lever 36 is connected by a rod 37 to a tripping device, not shown, which can for instance be an electro-magnetic tripping mechanism. Moreover, a lever 38 supported on a pivot' 39 is connected to the holder 16.3, this lever being connected to a recall device 40 which in this case is shown as a pressure gas piston.

This arrangement operates as follows. The position shown corresponds to the closed position of the breaker. For opening the breaker rod 37 is moved to the right by the tripping device, as indicated by the arrow. The left arm of the angle-lever 36 thus releases the retaining latch 34 which due to the tensile force of the insulating rod 17.1 slips off the pin 35 so that the insulatingrod moves upwards and the breaker opens in the manner already described in connection with FIG. 1. For closing the breaker, pressure gas is supplied to the underside of the piston of the recall device whereupon the insulating rod is moved downwards by lever 38. In the lower end position, parts 34, 35, 36 are again interlocked, for which purpose recall spring 34' attached to latch 34 and lever 36 is provided. Immediately after the breaker has closed, recall device 40 is exhausted again by means of a control valve which is not shown.

What we claim is:

1. The combination with a circuit breaker of the gas blast type including a hollow insulator column having one end in communication with a supply container of pressurized gas and the other in communication with a container structure housing gas pressure responsive actuating means for the circuit breaker contacts, and wherein said containerstructure is under voltage and continuously filled with the pressurized gas from said supply'container, of an operating mechanism for controlling said gas pressure responsive contact actuating means, said operating mechanism comprising a normally closed switching valve supported by said container structure, said' switching valve including a movable valve member having one side there-- of continuously subject to the gas pressure within said container structure and which always tends to move said valve member in the valve opening direction which is likewise the direction which gas flows through said valve to effect operation of said gas pressure responsive contact actuating means, a rod of insulating material, means applying a-tension force to said rod, linkage means interconnecting said rod with said movable valve member, saidlinkage means translating .said tension force in said rod to a force acting on said movable valve member in such direction as to maintain said movable valve memher in its closed position overcoming the counter valve opening force applied by the pressurized gas acting on the valve member, and means for releasing said tension force in said insulating rod thereby to allow said valve member to shift from its closed to its open position in response to the gas pressure within said container structure.

2. On operating mechanism for gas pressure responsive contact actuating means of a circuit breaker as defined in claim 1 wherein said means for applying and for releasing said tension force on said insulating rod is comprised of a fluid motor of the piston-cylinder type, said piston being connected to said insulating rod and being also a differential piston having one smaller end face thereof in I continuous communication with said pressurized gas supply container and the opposite larger end face thereof communicable with said pressurized supply container through a control valve to effect movement of said differential piston in the rod tension releasing direction.

3. An operating mechanism for gas pressure responsive contact actuating means of-a circuit breaker as defined in claim 1 wherein said means for applying and for releasing said tension force on said insulating rod is comprised of a fluid motor of the piston-cylinder type, said piston being connected to said insulating rod and spring loaded on one side by a compression spring to exert tension on said rod, and valve-controlled means for applying a fluid pressure to the opposite side of said piston to release the rod tensioning force exerted by said spring.

4. An operating mechanism for gas pressure responsive contact actuating means of a circuit breaker as defined in claim 1 wherein said means for applying and for releasing said tension force on said insulating rod is comprised of a fluid motor of the piston-cylinder type having the piston connected to said insulating rod for applying the rod tensioning force, and a releasable latch mechanism holding said rod in its tensioned state.

References Cited by the Examiner UNITED STATES PATENTS 2,491,112 12/1949 Jansson 200-148 X 2,783,338 2/1957 Beatty 200--l48 3,037,738 6/1962 Jackson et al 251l74 X 3,075,060 1/1963 Strom 200-148 FOREIGN PATENTS 1,052,502 3/ 1959 Germany.

KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER,-Examiner. P. E. CRAWFORD, Assistant Examiner. 

1. THE COMBINATION WITH A CIRCUIT BREAKER OF THE GAS BLAST TYPE INCLUDING A HOLLOW INSULATOR COLUMN HAVING ONE END IN COMMUNICATION WITH A SUPPLY CONTAINER OF PRESSURIZED GAS AND THE OTHER IN COMMUNICATION WITH A CONTAINER STRUCTURE HOUSING GAS PRESSURE RESPONSIVE ACTUATING MEANS FOR THE CIRCUIT BREAKER CONTACTS, AND WHEREIN SAID CONTAINER STRUCTURE IS UNDER VOLTAGE AND CONTINUOUSLY FILLED WITH THE PRESSURIZED GAS FROM SAID SUPPLY CONTAINER, OF AN OPERATING MECHANSIM FOR CONTROLLING SAID GAS PRESSURE RESPONSIVE CONTACT ACTUATING MEANS, AND OPERATING MECHANISM COMPRISING A NORMALLY CLOSED SWITCHING VALVE SUPPORTED BY SAID CONTAINER STRUCTURE, SAID SWITCHING VALVE INCLUDING A MOVABLE VALVE MEMBER HAVING ONE SIDE THEREOF CONTINUOUSLY SUBJECT OF THE GAS PRESSURE WITHIN SAID CONTAINER STRUCTURE AND WHICH ALWAYS TENDS TO MOVE SAID VALVE MEMBER IN THE VALVE OPENING DIRECTION WHICH IS LIKEWISE THE DIRECTON WHICH GAS FLOWS THROUGH SAID VALVE TO EFFECT OPERATION OF SAID GAS PRESSURE RESPONSIVE CONTACT ACTUATING MEANS, A ROD OF INSULATING MATERIAL, MEANS APPLYING A TENSION FORCE TO SAID ROD, LINKAGE MEANS INTERCONNECTING SAID ROD WITH SAID MOVABLE VALVE MEMBER, SAID LINKAGE MEANS TRANSLATING SAID TENSION FORCE IN SAID ROD TO A FORCE ACTING ON SAID MOVABLE VALVE MEMBER IN SUCH DIRECTION AS TO MAINTAIN SAID MOVABLE VALVE MEMBER IN CLOSED POSITION OVERCOMING THE COUNTER VALVE OPENING FORCE APPLIED BY THE PRESSURIZED GAS ACTING ON THE VALVE MEMBER, AND MEANS FOR RELEASING SAID TENSION FORCE IN SAID INSULATING ROD THEREBY TO ALLOW SAID VALVE MEMBER TO SHIFT FROM ITS CLOSED TO ITS OPEN POSITION IN RESPONSE TO THE GAS PRESSURE WITHIN SAID CONTAINER STRUCTURE. 